quarkusio/quarkus · error · IllegalArgumentException

The database attribute was not set for the @MongoEntity anno

Error message

The database attribute was not set for the @MongoEntity annotation and the database was not configured for the named Mongo Client via 'quarkus.mongodb.%s.database' or the connection string

What it means

The entity's @MongoEntity points at a named Mongo client (clientName is non-empty), but neither the annotation's database attribute, the named client's 'quarkus.mongodb.<clientName>.database' property, nor that client's connection string provides a database name.

Source

Thrown at extensions/panache/mongodb-panache-common/runtime/src/main/java/io/quarkus/mongodb/panache/common/runtime/BeanUtils.java:75

        }
        if (mongoClientConfig.connectionString().isPresent()) {
            String database = new ConnectionString(mongoClientConfig.connectionString().get()).getDatabase();
            if (database != null) {
                return database;
            }
        }

        if (mongoEntity == null) {
            throw new IllegalArgumentException(
                    "The database was not configured for the default Mongo Client via 'quarkus.mongodb.database' "
                            + "or the connection string");
        }
        if (mongoEntity.clientName().isEmpty()) {
            throw new IllegalArgumentException("The database attribute was not set for the @MongoEntity annotation "
                    + "and the database was not configured for the default Mongo Client via 'quarkus.mongodb.database' "
                    + "or the connection string");
        }
        throw new IllegalArgumentException(String.format(
                "The database attribute was not set for the @MongoEntity annotation and the database was not configured "
                        + "for the named Mongo Client via 'quarkus.mongodb.%s.database' or the connection string",
                mongoEntity.clientName()));
    }

    public static Optional<String> getDatabaseNameFromResolver() {
        return Optional.of(Arc.container().select(MongoDatabaseResolver.class))
                .filter(Predicate.not(InjectableInstance::isUnsatisfied))
                .map(InjectableInstance::get)
                .map(MongoDatabaseResolver::resolve)
                .filter(Predicate.not(String::isBlank));
    }

    private static <T> T firstInstanceWithoutQualifier(Iterable<InstanceHandle<T>> handles,
            Class<? extends Annotation> qualifier) {
        for (InstanceHandle<T> handle : handles) {
            InjectableBean<T> bean = handle.getBean();
            boolean match = false;

View on GitHub (pinned to e1c734241f)

Solutions

Set 'quarkus.mongodb.<clientName>.database=mydb' in application.properties (e.g. quarkus.mongodb.orders.database)
Set the database on the annotation: @MongoEntity(clientName="orders", database="mydb")
Embed the database in the named client's connection string: quarkus.mongodb.orders.connection-string=mongodb://host:27017/mydb

Example fix

// before (application.properties)
quarkus.mongodb.orders.connection-string=mongodb://orders-host:27017

// after
quarkus.mongodb.orders.connection-string=mongodb://orders-host:27017
quarkus.mongodb.orders.database=ordersdb

Defensive patterns

Strategy: validation

Validate before calling

MongoEntity anno = MyEntity.class.getAnnotation(MongoEntity.class);
String client = anno != null ? anno.clientName() : "";
if (!client.isEmpty()
        && config.getOptionalValue("quarkus.mongodb." + client + ".database", String.class).isEmpty()) {
    throw new IllegalStateException("Named client '" + client + "' has no database configured");
}

Try / catch

try {
    repository.find("byName", name).firstResult();
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("named Mongo Client")) {
        log.error("Missing quarkus.mongodb.<client>.database for named client", e);
    }
    throw e;
}

Prevention

For every named client (quarkus.mongodb.<name>.*), also define quarkus.mongodb.<name>.database
Double-check clientName spelling matches the config key exactly
Use Quarkus dev services / config mapping validation at startup to catch unconfigured named clients early

When it happens

Trigger: Entity annotated @MongoEntity(clientName="orders") with no database attribute, while 'quarkus.mongodb.orders.database' is unset and 'quarkus.mongodb.orders.connection-string' has no /database path part.

Common situations: Multi-client setups where developers configure the named client's hosts but forget its database; copying the default client's config pattern and omitting the per-client database; typos in the client property name so the named config is never picked up.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/543e7ef2b6e50564. Report an issue: GitHub.